1. Field
Various embodiments relate to electronic circuits and, particularly, to circuits, systems, and methods for discharging voltage from load capacitance circuits.
2. Description of the Related Art
Contemporary high voltage discharge circuits use multiple current sources or gated resistors to discharge voltages. Multiple current sources or gated resistors are required because the load capacitance may vary depending on the operation the chip is performing. Each current source requires individual tuning, which is dependent on the load capacitance.
In prior discharge circuits, the size of the current sources or gated resistors must be adjusted to the size of the capacitive load being discharged. In the case of nonvolatile memories, the capacitive load will be different depending on the high voltage operation being performed and on the size of the memory device. High voltage operations make a difference because different parts of the memory array are energized with high voltages for different operations (e.g., program and erase). Each high voltage operation requires a different size of current source or gated resistor, and this consumes extra circuit area. The exact value of the capacitive load may not be sufficiently known until circuit layout is complete. Therefore, different capacitive loads require time-consuming tuning, which usually occurs near the end of a design project.
Changes in array size mean that circuit reuse without additional tuning is also limited. Process variation that changes dielectric thicknesses will vary the load capacitance and, thus, will vary the discharge voltage slew rate. The discharge voltage slew rate is important to avoid a phenomenon known as “bipolar snapback,” which can cause a latch-up in electronic circuits.